int findLongestPath(vector<int> topSortOrder, vector<vector<int>>& g) {
    int n = topSortOrder.size();
    vector<int> dist(n,0);
    int ans = 0;
    for(int i=0;i<n;i++) {
        int node = topSortOrder[i];
        for(auto& ch: g[node]) {
            dist[ch] = max(dist[ch], 1 + dist[node]);
            ans = max(ans,dist[ch]);
        }
    }
    return ans;
}